Manchester United boss Ole Gunnar Solskjaer has opened the door to a new centre-half signing this summer.
Victor Lindelof partnered captain Harry Maguire in 35 of the 38 league matches but had a mixed season and United's other four centre halves made league six starts between them.
"We're always looking to improve the team and the squad," Solskjaer replied in response to the centre-back issue.
"I think we've been very, very solid at the back. Sometimes you might be exposed [when a player gets] in behind when you're pressing as high as we have done. We decided we're going to be a high pressing time when we can and if you don't take risks you won't improve.
"Once in a while we've been found some space behind us but I've not been concerned about it, no."